Alcohol abuse and dependence disorders are common in the general population, with conservative estimates suggesting that almost 1 in 5 Americans will develop an alcohol use disorder (AUD) during their lifetime. The public heath concerns associated with AUDs have been well-documented; nonetheless, important gaps in knowledge remain concerning the development and course of AUDs in the general population. To address these gaps, the proposed research will describe several important features associated with the natural course of AUDs. These include the diversity of AUD-related developmental trajectories, as well as the timing and sequencing of relationships that AUD trajectories share with common co-occurring conditions, such as cannabis use disorders, hard drug use disorders, and antisocial behavior disorders. The proposed research will also report data on the probability of relapse following the first AUD episode and the time to disorder recurrence for those with a second AUD episode. A model will also be tested for understanding the short- and longer-term outcomes of AUDs that, in turn, have implications for relapse-related processes following periods of sustained recovery. To accomplish these research aims, an existing data set from the Oregon Adolescent Depression Project (OADP) will be analyzed. The OADP is a community-based and multi-generational longitudinal study that spans the peak period for the emergence of sustained patterns of hazardous alcohol use, from adolescence through early adulthood. The research described in this proposal will address several issues not previously addressed in prior OADP publications. Four broad areas are emphasized that integrate OADP's longitudinal and developmental features. (1) Hazard functions that describe trends associated with the age of first onset for AUDs will be derived, and data will be reported on the time to recovery, the probability of relapse, and the time to disorder recurrence. (2) Subgroups of persons will be identified based on the developmental course of AUDs over the lifetime, and childhood risk factors and adult psychosocial outcomes associated with distinct trajectory subgroups will be reported. (3) The possible unidirectional and reciprocal relationships that AUDs share with other related disorders will be evaluated and documented. (4) Depressive disorders will be evaluated as possible scars following initial AUDs that, in turn, predict the likelihood of future relapse. Findings from this proposed research have the potential to inform theories of the epidemiology of AUDs, aid the development of screening tools to identify youth who are at risk for future AUDs, facilitate the development of targeted prevention programs and therapeutic interventions, and reduce the likelihood of relapse once beneficial behavior change has occurred.